Secondary Operations for Powder Metallurgy Parts

A sintered powder metallurgy (PM) part can be finished or treated just like any other metal part to achieve desired characteristics-corrosion resistance, improve strength ans hardness, surface wear resistance, edge-sharpness relief, porosity sealing, and control of size and surface finish.

Plating, coating, deburring, welding, furnace brazing, heat treating, and stem treating are among secondary operations that are used successfully in the process of fabricating finished PM parts.

Unlikes parts made using other metal forming processes, powder metallurgy parts can be repressed or coined, as well as sized, to densify or modify the surface shape and provide stricter dimensional control. Though oil impregnation, used on PM self-lubricating bearing components since the last 1920s, components can absorb 12%-30% oil by volume. Resin impregnation can also be preformed on PM parts to improve machinability or to prepare the surface for plating. Infiltration is a secondary process step used to either improve strength or seal parts and make the gas- or liquid-tight. Optionally, like resin impregnation, it can also be used to enhance machinability, improve ductility and prepare parts for plating.